Refrigerating apparatus



Filed March 31, 1930 IN VEN TOR Patented Sept. 5, 1933 UNITED STATES REFRIGERATING APPARATUS Jesse G. King, Dayton, Ohio, assignor to Frigidaire Corporation, Dayton, Ohio, a corporation of Delaware Application March 31, 1930. Serial No. 440,523

4 Claims.

The present invention relates to refrigerating system and more particularly to the control of the flow of refrigerant in the system.

One of the objects of the present invention is to provide for maintaining a predetermined level or provide for controlling the level within a refrigerant storage casing of the system from the exterior thereof.

More specifically it is a further object of the present invention to maintain the level or for varying the level of refrigerant within an evaporator from the exterior thereof.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing, wherein a preferred form of the present invention is clearly shown.

The figure in the drawing illustrates my improved refrigerating system including the evaporator.

One of the problems of refrigerating systems of the type in which lubricant is contained within the system for lubricating the moving parts thereof, for example the compressor of the compressor-condenser-expander type refrigerating system is the returning of the lubricant to the compressor after it has once been conveyed with the refrigerant to other parts of the system.

Another problem is that of confining the vaporization of the refrigerant to the evaporator so that the suction line leading from the evaporator to the compressor does not receive unyaporized refrigerant. These problems are particularly present in a system of the flooded type wherein a large quantity of liquid refrigerant is maintained within the evaporator and particularly so when a standard type of evaporator may be used for obtaining relatively high or relatively low refrigerating temperatures. For example, an evaporator may be used for cooling ice cream where it is desirable to maintain a, relatively low temperature or the same type of evaporator may be used for cooling cut flowers where a relatively higher temperature is to be maintained. In the first use abovestated the ebullition in the evaporator will be less violent than the second and in systems wherein the lubricant from the compressor is conveyed to the evaporator and floats on the liquid refrigerant therein, if the refrigerant level is maintained the same under both operating conditions, the oil return will be considerably different in one instance than the other, because the return of lubricant to the compressor is dependent upon, to a large extent, the fiow of gaseous refrigerant therethrough- The present invention contemplates adjusting the liquid level within the storage chamber so as to suit the conditions for the most efiicient oil return in accordance with the use to which the system is applied.

Referring to the drawing, I have showna casing 20 and for the purpose of illustrating one form of the invention I have shown this casing as an evaporator storage chamberfrom which depends a plurality of refrigerant conveying ducts 5 21 for conveying the refrigerant to the zone or place to be refrigerated. Refrigerant is delivered to the casing 29 through a pipe 23 and is withdrawn from the casing through a pipe 24. The pipe 23 is connected with a receiver 26 and the pipe 24 is connected to the low pressure side of a compressor 27, preferably as shown to the crank case thereof. The high pressure side of the compressor is connected with the condenser 29 which in turn is connected with the receiver 26". The compressor is herein shown as driven by a motor 30 through a belt 31 and the circuit of the motor is controlled by a snap switch 32 which is actuated by a metallic bellows 33. This bellows is responsive to the pressure within the low pressure side of the refrigerating system and is connected to such low pressure side by a pipe 34 connected with the pipe 24.

The casing 20 which is herein shown as a refrigerant containing chamber is formed of drawn tube is for conveying gaseous refrigerant from the free space above the liquid in the refrigerating chamber. Thehead 3'7 is also provided'with an opening 46 connected with the valve 40 and receives a screen 47. The size of this opening 46 is reduced to a small orifice 49 which provides a valve seat for a needle valve 51. A boss 52 which provides the inwardly extending portion of the opening 46, orifice 49 and the valve seat, is cylindrical in shape. A sleeve 53 is secured to the cylindrical portion of boss 52 and is provided with an inwardly extending ledge 54 which is bifurcated at 55 to receive a float lever 56. The float lever 56 is pivoted to the forks of the ledge 54 by a pin 58. The float lever is of the bell crank type, one end thereof carrying a fioat 60 and the other end a pin 61 which'latte'r carries the needle valve 51.

lubricant to the outlet 44.

'if the evaporator is used in a system where a It will be apparent from the foregoing that the flow of refrigerant through the evaporator will be controlled by the needle valve 51 which controls the flow of refrigerant from the receiver 26 and this flow is responsive to the float 60 so that when a predetermined quantity of refrigerant is contained within the chamber 20, the float will close or tend to close the needle valve and thus stop or impede the flow of refrigerant to the evaporator.

In carrying out the present invention I provide means for varying the buoyant effect of the float in order to vary the liquid level within the chamber 20 and I arrange this means so that it can be adjustable from the exterior of the system to thus permit the adjustment of the device without permitting refrigerant to escape. In the embodiment illustrated I increase and decrease the resistance offered to the movement of the float by a spring 62 which is arranged to urge the needle valve 51 from its seat. The spring is in the form of an inverted U, one leg thereof being connected with a rod 63 and the other end is perforated and straddles a reduced portion of the needle valve 51. A metal bellows 65 surrounds the rod'63 and has its inner end bonded thereto in sealed relation and the opposite end of the bellows 65 is bonded and sealed to the head 36 so that this bellows provides a flexible wall portion of the casing. The rod 63 extends a substantial distance within the bellows 65 and this extended portion is hollowed out to receive an adjusting screw 66 threaded into the head 37. The screw 66 is recessed as at 6'7 and the rod 63 is recessed to receive a ring 68. This ring is adapted to extend within the recess 67 and while it permits the turning of the screw 66 it prevents the longitudinally sliding thereof with respect to the rod 63.

It will be apparent from the foregoing that I have provided a closed system of refrigeration and I arrange for adjusting the level of refrigerant within the casing 20 from the exterior thereof. For example, if it is desirable to maintain a higher refrigerant level than that shown at '70 and consequently a higher oil level than that indicated at 71, it is necessary only to screw inwardly on the screw 66 to thus increase the tension of the spring 62. Therefore more energy will be necessary to close the valve and consequently a larger quantity of liquid must be contained within the casing 20 before the valve closes. Conversely, if it is desirable to decrease the liquid level from that illustrated, the screw 66 would be moved in the opposite direction, namely outwardly so as to decrease the tension of the spring 62. In this manner I provide means for returning lubricant to the compressor more readily. This same means can be utilized for preventing the return of liquid refrigerant to the suction line 24. When the evaporator is used in connection with a system in which a relatively low temperature is desired, ebullition within the evaporator and consequently through the layer of oil, floating on the liquid refrigerant, will be less and therefore less oil will be carried with the refrigerant to the outlet 44 of the evaporator. In order to increase the return of oil, I regulate the buoyant effect of the float so that a higher refrigerant level and therefore a higher oil level is maintained within the header 20 and consequently less agitation is necessary to deliver On the other hand,

relatively warmer temperature is to be maintained, in which system the ebullition is rather violent and due to this violent action, globules of liquid refrigerant are conveyed to the outlet 44, I regulate the screw 66 so as to maintain a lower level within the evaporator and therefore the refrigerant must boil more violently in order to deliver liquid refrigerant to the outlet 44. And by the inclusion of the flexible wall 65 I obtain these adjustments without opening the refrigerating system to atmosphere.

Another advantage of the present invention is that in the event that the small orifice 49 should become clogged with dirt, by my invention the screw 66 can be moved inwardly to such an extent to open the needle valve so as to permit a rush of liquid refrigerant through this small orifice to clean same.

It is also to be understood that by the present arrangement I provide an adjustment from the exterior of the system so as to maintain a constant level within the evaporator, for example if the seat for the needle valve 51 or the needle valve should wear, the float would rise to a higher level by the needle valve closed upon its seat. By the adjustment through 66 I can return the level to the desired position.

While the form of embodiment of the invention as herein disclosed constitutes a preferred form, it is to be understood that other forms ion might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. An evaporator for a refrigerating system comprising in combination, a closed evaporating chamber containing a quantity of liquid refrigerant, an inlet connection and an outlet connection for said chamber, said outlet connection being disposed above the quantity of liquid refrigerant in said chamber, refrigerant flow control means for controlling the flow of liquid refrigerant to said chamber through said inlet connection and for preventing liquid refrigerant from rising above a predetermined level in said chamber, said control means including a float within,

the chamber responsive to the level of liquid refrigerant therein and a valve operatively connected with said float, the walls of said chamber having a flexible portion, and means for varying the buoyant effect of said float, said last named means being operatively connected with the flow 2. An evaporator for a refrigerating system comprising in combination, a closed evaporating chamber containing a quantity of liquid refrigerant, an inlet connection and an outlet connection for said chamber, said outlet connection being disposed above the quantity of liquid refrigerant in said chamber, refrigerant flow control means for controlling the flow of liquid refrigerant to said chamber through said inlet connection and for preventing liquid refrigerant from rising above a predetermined level in said chamber, said control means including a float within the chamber responsive to the level of liquid refrigerant therein and a valve operatively connected with said float, the walls of said chamber having a flexible portion, and means for varying the buoyant effect of said float, said last named means including a yieldable connection between said flow control means and said flexible wall portion and including adjustable means exterior of the chamber and associated with said flexible wall portion for flexing the same.

3. An evaporator for a refrigerating system comprising in combination, a closed evaporating chamber containing a quantity of liquid refrigerant, an inlet connection and an outlet connec tion for said chamber, said outlet connection being disposed above the quantity of liquid refrig-v erant in said chamber, refrigerant flow control means for controlling the flow of liquid refrigerant to said chamber through said inlet connection and for preventing liquid refrigerant from rising above a predetermined level in said chamher, said control means including a float within the chamber responsive to the level of liquid refrigerant therein and a valve operatively connected with said float, the walls of said chamber having a flexible portion, and means for varying the buoyant effect of said float, said last named means including a yieldable connection between said flow control means and said flexible wall portion and including adjustable means exterior of the chamber and associated with said flexible Wall portion for flexing said wall and for maintaining same in said adjusted flexed position.

4. An evaporator for a refrigerating system comprising in combination, a closed evaporating chamber containing a quantity of liquid refrigerant, an inlet connection and an outlet connection for said chamber, said outlet connection being disposed above the quantity of liquid refrigerant in said chamber, refrigerant flow control means for controlling the flow of liquid refrigerant to said chamber through said inlet connection and for preventing liquid refrigerant from rising above a predetermined level in said chamber, said control means including a float within the chamber responsive to the level of liquid refrigerant therein and a valve operatively connected with said float, the walls of said chamber having a flexible portion, and means for varying the buoyant effect of said float, said last named means including a movable member having a yieldable connection between said flow control means and said member, said last named means also including a hollow flexible member sealed to one wall of said chamber and to said movable member, and adjustabe means extending inward- 1y from the exterior of said chamber and engaging said movable member for moving said member with respect to a'wall of said chamber.

JESSE G. KING. 

